This doesn't quite stub out the file load itself, but to do that you'd have to make assumptions about what YAML.load_file does under the covers, and that's not a good idea. Since it's safe to assume that the YAML implementation is already tested, you can use the code above to replace the entire call with your parsed-from-text fixture.

If you want to test that the correct filename is passed to load_file, replace the stub with an expectation:

If the idea is to put an expectation on something, I don't see much benefit on this approach of calling YAML.load to fake the return. YAML.load_file actually returns a hash, so instead of doing all that my suggestion would be to simply return a hash: